In recent years, there has been considerable interest in the production of glass fibers. Due to the increased usage of glass fibers, this interest has been particularly focused on increasing the production of individual fiber forming stations.
In the production of fibers, molten glass is typically passed through orificed tips or projections in a bushing or a stream feeder to create individual fibers. As the molten streams of glass flow through the orificed projections for attenuation into fibers, the fiber-forming environment below the bushing must be carefully controlled for a stable fiber-forming operation.
Conventionally, the environment adjacent the streams of molten glass is controlled by placing metallic heat exchanging units or fin shields beneath the bushing and between rows of tips. Such fin shield units have been used for many years to control the fiber forming region beneath the bushing. Such a heat exchanging device is described in U.S. Pat. No. 2,908,036.
Over the years, the number of fibers capable of being produced by a single bushing has increased greatly. In the past it was common for a bushing to produce about 200 fibers. Today, bushings can produce 2,000, or more, fibers. As the number of fibers per bushing continues to increase, problems with conventional fiber forming processes and apparatus have arisen.
As bushings are produced to manufacture even larger numbers of fibers per bushing and as the throughput per bushing tip is increased, environmental control by conventional fin shield units can become inadequate. There has been considerable activity in the glass fiber forming field to develop a process and apparatus for controlling the fiber forming environment in such bushings.